The present invention relates to a system for measuring and monitoring loads incurred by a load detector mounted on a press.
Of prior art load monitoring systems, there has been, so far, a well known system in which a load detector such as a strain gauge and a piezoelectric element mounted on a slide or an up/down rod of the press detects a load applied to a work piece in the form of an electric signal during pressing operations of the press, and a load meter indicates, for example, a maximum value of the detected load on a display.
In this type of a conventional load monitoring system, an output from the load monitoring system and an output from a slide-position detector provided in the press (for example, a rotary cam switch mounted on a driving shaft) are simultaneously supplied to an electromagnetic oscillograph for display, and then an operator of the press converts the display results to digital values on the basis of the calibrated initial values in order to obtain load changes with respect to positions of the slide (that is, an up or down position of the slide) in the press.
Such a load monitoring system, however, had disadvantages in that the system involves a great amount of time in calibration as well as setting of the system and is troublesome in its handling, thereby requiring considerable operator's skill.